/*
 * subst.c -- 在字符串中左侧排名
 */
#include <stdio.h>
#define PSQR(x) printf("The square of  " #x " is %d \n", ((x) * (x)))

int main(void)
{
    int y = 5; 
    PSQR(y);
    PSQR(2 + 4);
    return 0;
}
